Intake manifolds in internal combustion engines may include various ports for introducing gases into the intake manifold. In some examples, the ports may be coupled to systems which utilize the vacuum generated within the intake manifold to supplement various operations. For example, the intake manifold may be in fluidic communication with a positive crankcase ventilation system, a brake system, an evaporative emission system (e.g., vapor canisters), etc. However, objectionable noises, such as whistling, may be generated within the ports and the intake manifold during engine operation due to the flow characteristics within the aforementioned components. Furthermore, in some systems gases introduced into the intake manifold from the ports may not fully mix with the air in the intake manifold, increasing combustion variability and decreasing engine efficiency.
Some intake systems have used ramps positioned upstream of the ports in the intake manifold to reduce unwanted noise, as well as to promote mixing. However, the inventors herein have recognized various shortcomings with such an above approach. For example, ramps may increase losses within the intake manifold, thereby decreasing pressure within the intake manifold. Decreased intake manifold pressure may in turn degrade engine operation during certain operating conditions, such as when the throttle is fully open. Furthermore, it may be unfeasible to incorporate a ramp into an intake manifold using certain construction techniques, such as shell molding. Therefore, to incorporate ramps into an intake manifold, retrofitting of the intake manifold may be required or alternatively more complex and expensive construction techniques may be needed, increasing production costs.
As such, various example systems and approaches are described herein. In one example an intake system is provided. The intake system may include an intake manifold coupled to an engine and a vacuum port located in said intake manifold and in an air flow path downstream of a throttle body and upstream of a plurality of intake runners. The vacuum port may include a molded flow disruptor including a cross-beam traversing an outlet of the vacuum port. The intake system may further include a vacuum passage coupling the vacuum port to a vehicle subsystem.
In this way, it is possible to reduce unwanted noises while promoting mixing of the gases from the port with the intake air. In particular the cross-beam splits the flows of the gases through the vacuum port generating a turbulent wake downstream of the cross-beam in the intake manifold, thereby promoting mixing of the gas from the vacuum port with gas from the throttle body. Furthermore, in some embodiments the intake manifold and flow disruptor may be integrally molded using shell molding. In this way, the intake manifold and vacuum port may be manufactured utilizing a low cost technique.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.